1. Technical Field
The present invention relates to a substrate connection system which connects between substrates via a harness and an inkjet recording device that connects between substrates via a harness.
2. Related Art
A configuration for connecting between substrates via a harness is widely used in the fields of electric equipment and electronic equipment. For example, an inkjet recording device which prints an image on a sheet by ejecting ink from a nozzle in an inkjet head uses a configuration for connecting a sub substrate on which a drive circuit of the inkjet head is mounted to a main substrate of a printer engine via a harness.
Then, a line head system inkjet recording device which prints an image in a state in which inkjet heads are fixed while the sheet is being transferred includes a plurality of inkjet heads which is arrayed in a line in accordance with a print width of the sheet. In addition, a multi-color system inkjet recording device which prints a color image by using inks of a plurality of colors includes a plurality of inkjet heads corresponding to the ink colors.
In the inkjet recording device which includes the plurality of inkjet heads as mentioned above, each sub substrate on which the drive circuit of each inkjet head is mounted is connected to a common main substrate via the harness. Then, a signal which contains individual contents according to an ink ejection pattern of each inkjet head that the drive circuit of each sub substrate drives is output from the main substrate to each sub substrate.
Accordingly, it is important to correctly connect the main substrate with each sub substrate in order to transmit a signal corresponding to the drive circuit of each sub substrate to the correct sub substrate on which the drive circuit concerned is mounted.
Incidentally, signals to be transmitted from the main substrate to each sub substrate are all control signals for driving the inkjet heads by the drive circuits and a communication speed and communication contents demanded in transmission of these control signals are basically the same among all of the sub substrates. Therefore, in many cases, the harnesses and connectors used for connecting the main substrate and each of the sub substrates are made common for reduction in component costs.
If the common harness and connector are used as mentioned above, the possibility that the main substrate and each sub substrate may be connected together in an erroneous pattern due to faulty connection and a signal to be transmitted for one drive circuit may be erroneously transmitted to the sub substrate on which another drive circuit is mounted will be increased.
Such faulty connection is detected by the use of a device which has been proposed so far and is configured to autonomously diagnose a state of connection between two objects (see Japanese Patent Application Laid-Open Publication No. 2010-55384 as Patent Document 1). In the device relevant to this proposal, a master-side board and a slave-side board are connected together by a cable with connector, an operation signal line of the master-side board which is communicated with the cable is grounded and an operation signal line of the slave-side board is pulled up.
Thereby, the connection state between the master-side board and the slave-side board is detected depending on whether a signal level appearing in the operation signal line of the slave-side board is a ground level or a signal level of a pull-up destination.